Flexible modeling and execution of choreographies

Approaches to address domain specific problems often share overlapping requirements but typically satisfy them in a unique manner for example using service-oriented concepts. The notion of Collaborative, Dynamic & Complex (CDC) systems has been proposed in literature to address the requirements of application domains such as eScience and Collective Adaptive Systems in a unified, generic manner. CDC systems are characterized by dealing with potentially large amounts of data and/or participating applications which engage in complex interactions specified by some collaboration protocol. Furthermore, the need for adaptation mechanisms is a common requirement and users from these application domains are typically no IT experts. The choreography concept originally known from collaborations in the business domain captures the interaction between independent parties from a global perspective. Each party is denoted as a choreography participant, which is implemented by a workflow or a service. This concept provides a way to model and execute for example complex eScience experiments involving multiple scientific fields, scientific methods, and time and/or length scales as a set of coupled workflows. However, typical choreography concepts as described in literature do not provide the desired level of flexibility and ease of use in both modeling and execution to address the requirements of users in CDC system application domains such as eScience. Thus, existing choreography concepts have to be considerably extended by introducing the Model-as-you-go for Choreographies approach in this thesis as a central notion providing capabilities for the flexible modeling and execution of choreographies. In the context of this approach, we provide a concept for fostering reuse in choreography modeling in the form of so-called choreography fragments. Such fragments can be extracted from existing and inserted into new choreography models in order to save time as well as reuse established and approved logic by inexperienced modelers in a less error-prone manner. Furthermore, we provide support for the user-driven control of the complete choreography life cycle. This effectively allows users to automatically deploy the workflow models implementing a choreography as well as starting, pausing, resuming, and terminating a choreography instance, which is formed through the collective execution of workflow instances. Most importantly, the underlying complexity of managing a set of coupled workflow instances is completely hidden from the users. Additional flexibility is given by a concept that allows to re-run already executed choreography logic in order to enforce the convergence of a calculation towards a particular result or to react to errors with parameter changes. The proposed concepts are implemented in a message-based system, the ChorSystem, which is able to handle the challenges of choreography life cycle management from deployment, to run time control and the re-run of logic. Furthermore, the modeling and run time monitoring are integrated into one graphical tool supporting the seamless transition from modeling to execution of choreographies. The concepts, their supporting algorithms, and the prototypical ChorSystem are validated by a set of case studies from different CDC system application domains and evaluated by performance measurements showing the practical applicability

Mashups: An Approach to Overcoming the Business/IT Gap in Service-Oriented Architectures

For quite a long time already, great importance has been attached to the concept of Service-Oriented Architectures for future IT-architectures. However, a major challenge in implementing this concept lies in the gap between the functional department and IT department. Mashups, an architecture also based on services, try to avoid this gap by letting the user himself integrate the services. The following article analyzes similarities and differences between both architecture approaches, and explains to what extent and in which cases Mashups could complement a Service-Oriented Architecture

Domain-Specific Modelling for Coordination Engineering

Multi-core processors offer increased speed and efficiency on various devices, from desktop computers to smartphones. But the challenge is not only how to gain the utmost performance, but also how to support portability, continuity with prevalent technologies, and the dissemination of existing principles of parallel software design. This thesis shows how model-driven software development can help engineering parallel systems. Rather than simply offering yet another programming approach for concurrency, it proposes using an explicit coordination model as the first development artefact. Key topics include: Basic foundations of parallel software design, coordination models and languages, and model-driven software development How Coordination Engineering eases parallel software design by separating concerns and activities across roles How the Space-Coordinated Processes (SCOPE) coordination model combines coarse-grained choreography of parallel processes with fine-grained parallelism within these processes Extensive experimental evaluation on SCOPE implementations and the application of Coordination Engineerin

Mediated forensics and militant evidence : rethinking the camera as weapon

This article focuses on new media technologies and practices that are reshaping how human rights media activism is practiced, disseminated and received. Through an examination of two works by the research agency Forensic Architecture, we examine how these new technologies and practices aim to reframe and deploy forms of raw media evidence in human rights struggles and broader modes of political activism. We also consider how these nascent forms of activist media practice are indebted to the broader legacies of radical documentary practice, particularly through the theoretical lineage of the “camera as weapon.” The new technological and aesthetic strategies being developed and utilized by these groups are radically reshaping investigatory methodologies and collaborative practices across contemporary human rights, documentary, and new media practice. Ultimately, within these new ecologies of media practice, raw forms of media evidence are reframed and redeployed; entering into larger assemblages and ecologies to examine – and concomitantly resist – formations of political power and state violence. This is a practice that we term “mediated forensics.

The CHORCH Approach: How to Model B2Bi Choreographies for Orchestration Execution

The establishment and implementation of cross-organizational business processes is an implication of today's market pressure for efficiency gains. In this context, Business-To-Business integration (B2Bi) focuses on the information integration aspects of business processes. A core task of B2Bi is providing adequate models that capture the message exchanges between integration partners. Following the terminology used in the SOA domain, such models will be called choreographies in the context of this work. Despite the enormous economic importance of B2Bi, existing choreography languages fall short of fulfilling all relevant requirements of B2Bi scenarios. Dedicated B2Bi choreography standards allow for inconsistent outcomes of basic interactions and do not provide unambiguous semantics for advanced interaction models. In contrast to this, more formal or technical choreography languages may provide unambiguous modeling semantics, but do not offer B2Bi domain concepts or an adequate level of abstraction. Defining valid and complete B2Bi choreography models becomes a challenging task in the face of these shortcomings. At the same time, invalid or underspecified choreography definitions are particularly costly considering the organizational setting of B2Bi scenarios. Models are not only needed to bridge the typical gap between business and IT, but also as negotiation means among the business users of the integration partners on the one hand and among the IT experts of the integration partners on the other. Misunderstandings between any two negotiation partners potentially affect the agreements between all other negotiation partners. The CHORCH approach offers tailored support for B2Bi by combining the strengths of both dedicated B2Bi standards and formal rigor. As choreography specification format, the ebXML Business Process Specification Schema (ebBP) standard is used. ebBP provides dedicated B2Bi domain concepts such as so-called BusinessTransactions (BTs) that abstractly specify the exchange of a request business document and an optional response business document. In addition, ebBP provides a format for specifying the sequence of BT executions for capturing complex interaction scenarios. CHORCH improves the offering of ebBP in several ways. Firstly, the execution model of BTs which allows for inconsistent outcomes among the integration partners is redefined such that only consistent outcomes are possible. Secondly, two binary choreography styles are defined as B2Bi implementation contract format in order to streamline implementation projects. Both choreography styles are formalized and provided with a formal execution semantics for ensuring unambiguity. In addition, validity criteria are defined that ensure implementability using BPEL-based orchestrations. Thirdly, the analysis of the synchronization dependencies of complex B2Bi scenarios is supported by means of a multi-party choreography style combined with an analysis framework. This choreography style also is formalized and standard state machine semantics are reused in order to ensure unambiguity. Moreover, validity criteria are defined that allow for analyzing corresponding models for typical multi-party choreography issues. Altogether, CHORCH provides choreography styles that are B2Bi adequate, simple, unambiguous, and implementable. The choreography styles are B2Bi adequate in providing B2Bi domain concepts, in abstracting from low-level implementation details and in covering the majority of real-world B2Bi scenarios. Simplicity is fostered by using state machines as underlying specification paradigm. This allows for thinking in the states of a B2Bi scenario and for simple control flow structures. Unambiguity is provided by formal execution semantics whereas implementability (for the binary choreography styles) is ensured by providing mapping rules to BPEL-based implementations. The validation of CHORCH's choreography styles is performed in a twofold way. Firstly, the implementation of the binary choreography styles based on Web Services and BPEL technology is demonstrated which proves implementability using relatively low-cost technologies. Moreover, the analysis algorithms for the multi-party choreography styles are validated using a Java-based prototype. Secondly, an abstract visualization of the choreography styles based on BPMN is provided that abstracts from the technicalities of the ebBP standard. This proves the amenability of CHORCH to development methods that start out with visual models. CHORCH defines how to use BPMN choreographies for the purpose of B2Bi choreography modeling and translates the formal rules for choreography validity into simple composition rules that demonstrate valid ways of connecting the respective modeling constructs. In summary, CHORCH allows integration partners to start out with a high-level visual model of their interactions in BPMN that identifies the types and sequences of the BusinessTransactions to be used. For multi-party choreographies, a framework for analyzing synchronization dependencies then is available. For binary choreographies, an ebBP refinement can be derived that fills in the technical parameters that are needed for deriving the implementation. Finally, Web Services and BPEL based implementations can be generated. Thus, CHORCH allows for stepwise closing the semantic gap between the information perspective of business process models and the corresponding implementations. It is noteworthy that CHORCH uses international standards throughout all relevant layers, i.e., BPMN, ebBP, Web Services and BPEL, which helps in bridging the heterogeneous IT landscapes of B2Bi partners. In addition, the adoption of core CHORCH deliverables as international standards of the RosettaNet community give testament to the practical relevance and promise dissemination throughout the B2Bi community.Betriebsübergreifende Geschäftsprozessintegration ist eine logische Konsequenz allgegenwärtigen Wettbewerbsdrucks. In diesem Kontext fokussiert Business-To-Business integration (B2Bi) auf die Informationsaustausche zwischen Unternehmen. Eine B2Bi-Kernanforderung ist die Bereitstellung adäquater Modelle zur Spezifikation der Nachrichtenaustausche zwischen Integrationspartnern. Diese werden im Rahmen dieser Arbeit in Anlehnung an Service-orientierte Architekturen (SOA)-Terminologie Choreographien genannt. Bestehende Choreographiesprachen decken die Anforderungen an B2Bi-Choreographien nicht vollständig ab. Dedizierte B2Bi-Choreographiestandards definieren inkonsistente Austauschprozeduren für grundlegende Interaktionen und nur unvollständige Semantiken für fortgeschrittene Interaktionen. Formale oder Technik-getriebene Choreographiesprachen bieten die benötigte Präzision, lassen aber Domänenkonzepte vermissen oder operieren auf einer niedrigen Abstraktionsebene. Angesichts solcher Mängel wird die Spezifikation valider und vollständiger B2Bi-Choreographien zu einer echten Herausforderung. Gleichzeitig sind mangelhafte Choreographiemodelle gerade im B2Bi-Bereich besonders problematisch, da diese nicht nur zwischen Fach- und IT-Abteilung, sondern auch über Unternehmensgrenzen hinweg eingesetzt werden. Der CHORCH-Ansatz schafft an dieser Stelle mittels maßgeschneiderter Choreographien Abhilfe, welche die Vorteile von B2Bi-Choreographien und von formalen Ansätzen kombinieren. Als Ausgangspunkt wird das ebXML Business Process Specification Schema (ebBP) verwendet, das als B2Bi-Choreographiestandard Domänenkonzepte wie zum Beispiel sogenannte BusinessTransactions (BTs) bietet. Eine BT ist der Basisbaustein von B2Bi-Choreographien und spezifiziert den Austausch eines Geschäftsdokuments sowie eines optionalen Antwortdokuments. Darüber hinaus bietet ebBP ein Format zur Spezifikation von BT-Kompositionen zur Unterstützung komplexer Interaktionen. CHORCH erweitert ebBP wie folgt. Erstens, das Ausführungsmodell für BTs wird neu definiert, um inkonsistente Ergebniszustände zu eliminieren. Zweitens, für Entwicklungsprojekte werden zwei binäre Choreographieklassen definiert, die als B2Bi-Implementierungskontrakt dienen sollen. Die Formalisierung beider Klassen sowie formale operationale Semantiken gewährleisten Eindeutigkeit, während Validitätskriterien die Ausführbarkeit entsprechender Modelle mittels BPEL-basierter Orchestrationen garantieren. Drittens, zur Analyse der Synchronisationsbeziehungen komplexer B2Bi-Szenarien wird eine Multi-Party-Choreographieklasse nebst Analyseframework definiert. Wiederum wird für diese Klasse eine Formalisierung definiert, die mittels Standard-Zustandsautomatensemantik Eindeutigkeit gewährleistet. Ferner garantieren Validitätskriterien die Anwendbarkeit der definierten Analysealgorithmen. Insgesamt bieten die Choreographieklassen des CHORCH-Ansatzes ein B2Bi-adäquates, einfaches, eindeutiges und implementierbares Modell der Nachrichtenaustausche zwischen B2Bi-Partnern. B2Bi-Adäquatheit wird durch Verwendung von B2Bi-Domänenkonzepten, Abstraktion von rein technischen Kommunikationsdetails und Abdeckung der meisten praktisch relevanten B2Bi-Szenarien gewährleistet. Einfachheit ist ein Ausfluss der Verwendung eines Zustandsmaschinen-basierten Modellierungsparadigmas, das die Definition des Interaktionsfortschritts in Form von Zuständen sowie einfache Kontrollflussstrukturen ermöglicht. Eindeutigkeit wird durch die Verwendung formaler Semantiken garantiert, während Implementierbarkeit (für die beiden binären Choreographieklassen) durch Angabe von Mapping-Regeln auf BPEL-Orchestrationen sichergestellt wird. Die Validierung der CHORCH-Choreographieklassen erfolgt in zweierlei Hinsicht. Erstens, die Implementierbarkeit der binären Choreographieklassen mit Hilfe von Web Services und BPEL wird durch die Definition entsprechender Mappingregeln belegt. Weiterhin wird das Analyseframework der Multi-Party-Choreographieklasse als Java-Prototyp implementiert. Zweitens, für alle Choreographieklassen wird eine abstrakte Visualisierung auf BPMN-Basis definiert, die von diversen technischen Parametern des ebBP-Formats abstrahiert. Damit wird die Integrierbarkeit der CHORCH-Choreographieklassen in Entwicklungsansätze, die ein visuelles Modell als Ausgangspunkt vorsehen, belegt. CHORCH definiert, wie sogenannte BPMN-Choreographien zum Zweck der B2Bi-Choreographiemodellierung zu verwenden sind und übersetzt die Validitätskriterien der CHORCH-Choreographieklassen in einfache Modell-Kompositionsregeln. In seiner Gesamtheit bietet CHORCH somit einen Ansatz, mit Hilfe dessen B2Bi-Partner zunächst die Typen und zulässigen Reihenfolgen ihrer Geschäftsdokumentaustausche auf Basis eines abstrakten visuellen BPMN-Modells identifizieren können. Im Fall von Multi-Party-Choreographien steht dann ein Framework zur Analyse der Synchronisationsbeziehungen zwischen den Integrationspartnern zur Verfügung. Im Fall von binären Choreographien können ebBP-Verfeinerungen abgeleitet werden, welche die Modelle um technische Parameter anreichern, die zur Ableitung einer Implementierung benötigt werden. Diese ebBP-Modelle sind in Web Services- und BPEL-basierte Implementierungen übersetzbar. Damit erlaubt CHORCH die schrittweise Überbrückung der semantischen Lücke zwischen der Informationsaustauschperspektive von Geschäftsprozessmodellen und den zugehörigen Implementierungen. Ein beachtenswerter Aspekt des CHORCH-Ansatzes ist die Verwendung einschlägiger internationaler Standards auf allen Abstraktionsebenen, im Einzelnen BPMN, ebBP, Web Services und BPEL. Die Verwendung von Standards trägt dem heterogenen Umfeld von B2Bi-Szenarien Rechnung. Zusätzlich wurden Kernergebnisse des CHORCH-Ansatzes als internationale Standards der RosettaNet-B2Bi-Community veröffentlicht. Dies belegt die praktische Relevanz des Ansatzes und fördert die Verbreitung innerhalb der B2Bi-Community

Immersive Participation:Futuring, Training Simulation and Dance and Virtual Reality

Dance knowledge can inform the development of scenario design in immersive digital simulation environments by strengthening a participant’s capacity to learn through the body. This study engages with processes of participatory practice that question how the transmission and transfer of dance knowledge/embodied knowledge in immersive digital environments is activated and applied in new contexts. These questions are relevant in both arts and industry and have the potential to add value and knowledge through crossdisciplinary collaboration and exchange. This thesis consists of three different research projects all focused on observation, participation, and interviews with experts on embodiment in digital simulation. The projects were chosen to provide a range of perspectives across dance, industry and futures studies. Theories of embodied cognition, in particular the notions of the extended body, distributed cognition, enactment and mindfulness, offer critical lenses through which to explore the relationship of embodied integration and participation within immersive digital environments. These areas of inquiry lead to the consideration of how language from the field of computer science can assist in describing somatic experience in digital worlds through a discussion of the emerging concepts of mindfulness, wayfinding, guided movement and digital kinship. These terms serve as an example of how the mutability of language became part of the process as terms applied in disparate disciplines were understood within varying contexts. The analytic tools focus on applying a posthuman view, speculation through a futures ethnography, and a cognitive ethnographical approach to my research project. These approaches allowed me to examine an ecology of practices in order to identify methods and processes that can facilitate the transmission and transfer of embodied knowledge within a community of practice. The ecological components include dance, healthcare, transport, education and human/computer interaction. These fields drove the data collection from a range of sources including academic papers, texts, specialists’ reports, scientific papers, interviews and conversations with experts and artists.The aim of my research is to contribute both a theoretical and a speculative understanding of processes, as well as tools applicable in the transmission of embodied knowledge in virtual dance and arts environments as well as digital simulation across industry. Processes were understood theoretically through established studies in embodied cognition applied to workbased training, reinterpreted through my own movement study. Futures methodologies paved the way for speculative processes and analysis. Tools to choreograph scenario design in immersive digital environments were identified through the recognition of cross purpose language such as mindfulness, wayfinding, guided movement and digital kinship. Put together, the major contribution of this research is a greater understanding of the value of dance knowledge applied to simulation developed through theoretical and transformational processes and creative tools

ECLAP 2012 Conference on Information Technologies for Performing Arts, Media Access and Entertainment

It has been a long history of Information Technology innovations within the Cultural Heritage areas. The Performing arts has also been enforced with a number of new innovations which unveil a range of synergies and possibilities. Most of the technologies and innovations produced for digital libraries, media entertainment and education can be exploited in the field of performing arts, with adaptation and repurposing. Performing arts offer many interesting challenges and opportunities for research and innovations and exploitation of cutting edge research results from interdisciplinary areas. For these reasons, the ECLAP 2012 can be regarded as a continuation of past conferences such as AXMEDIS and WEDELMUSIC (both pressed by IEEE and FUP). ECLAP is an European Commission project to create a social network and media access service for performing arts institutions in Europe, to create the e-library of performing arts, exploiting innovative solutions coming from the ICT

Scientific Workflows: Moving Across Paradigms

Modern scientific collaborations have opened up the opportunity to solve complex problems that require both multidisciplinary expertise and large-scale computational experiments. These experiments typically consist of a sequence of processing steps that need to be executed on selected computing platforms. Execution poses a challenge, however, due to (1) the complexity and diversity of applications, (2) the diversity of analysis goals, (3) the heterogeneity of computing platforms, and (4) the volume and distribution of data. A common strategy to make these in silico experiments more manageable is to model them as workflows and to use a workflow management system to organize their execution. This article looks at the overall challenge posed by a new order of scientific experiments and the systems they need to be run on, and examines how this challenge can be addressed by workflows and workflow management systems. It proposes a taxonomy of workflow management system (WMS) characteristics, including aspects previously overlooked. This frames a review of prevalent WMSs used by the scientific community, elucidates their evolution to handle the challenges arising with the emergence of the “fourth paradigm,” and identifies research needed to maintain progress in this area